After ruling the fall in the ratings, the network hasn’t had much to sing about ever since its prized reality competition series started its winter break in December. NBC’s primetime average has dropped 16 percent since the beginning of the year. Freshman comedies Go On and The New Normal – previously boosted with a Voice lead-in – fell to season-low performances this week. A new Monday-night drama launched last month, Deception, is delivering weak numbers. And now another midseason drama, the medical show Do No Harm, had its series premiere Thursday night and set a broadcast ratings record.

Not a good record.

Do No Harm ranks as the lowest-rated in-season broadcast scripted series debut in TV history among the Big Four networks (since at least 1987 when the current ratings measurement system was adopted). It’s also the least-watched in-season broadcast drama premiere ever among the Big Four. Do No Harm didn’t do much of anything with 3.1 million viewers and a 0.9 adults 18-49 rating among adults 18-49. The telecast was down 55 percent from the premiere of Awake in the slot last March.

The show wasn’t much helped by critics, who scored the show an average of 38 out of 100 on Metacritic. It also wasn’t aided by its 10 p.m. time slot. This is the old ER slot, so a medical drama makes historical sense (even one with a weird Dr. Jekyll and Mr. Hyde twist). But it’s been a long time since ER was on the air. NBC had been running the very modestly rated Rock Center with Brian Williams in this hour, so there hasn’t been a lot of viewers hanging around this neighborhood lately.

In case you’re wondering, the previous all-time demo-low scripted series premiere Big Four record-holder is a tie between NBC’s short-live sitcom Bent, which launched last year, and Fox’s 2008 comedy effort The Return of Jezebel James starring Parker Posey. A different way to look at this: The Return of Jezebel James delivered such a terrible performance that despite all the broadcast ratings woes over the last decade it set a bar so low that it wasn’t broken for five years.

NBC was able to give 30 Rock a lift for its series finale last night, however. The last episode of the acclaimed Tina Fey comedy series had 4.8 million viewers and a 1.9 rating, up 36 percent this week to a season high.

Also Thursday: The return of CBS’ Big Bang Theory to originals easily beat Fox’s American Idol, which fell 12 percent this week. Glee fell 19 percent. ABC’s Grey’s Anatomy dipped 7 percent to a series low. Scandal was up 4 percent. The CW’s Vampire Diaries was steady. CBS’ lineup dipped slightly from their last original episodes.